Gas-Enhanced Surgical Instrument with Mechanism for Cylinder Puncture

ABSTRACT

A surgical instrument for providing an ionized gas to a surgical site includes a receptacle for a cylinder of pressurized surgical gas and a frame having a port near the distal end for emitting the surgical gas. A passageway extending between the receptacle and the port delivers the surgical gas to an electrode that is adapted for connection to a source of electrosurgical energy. A puncture assembly for rupturing a seal on the cylinder to release the surgical gas into the passageway includes a spring movable between a first state for storing mechanical energy and a relaxed state. An actuator is operable to move the spring to the relaxed state. A puncture pin is operatively coupled to the spring such that energy released by movement of the spring to the relaxed state is effective to move the puncture pin relative to the cylinder to rupture the seal.

BACKGROUND

1. Technical Field

The present disclosure relates to an apparatus for surgically treatingtissue with a pressurized gas. In particular, the disclosure relates toan apparatus with a mechanism for releasing the gas from a cylinder ortank.

2. Background of Related Art

Surgical instruments are commonly used for procedures such as tissuedivision, dissection, ablation, coagulating and arresting blood loss intissue. One type of instrument employs a heated probe to arrest bleedingin a technique called thermic coagulation. Heat may be conducted from arelatively hot probe tip to the tissue to be treated by moving the probeinto contact or into close proximity with the tissue. The probe mayadhere to the tissue while the tissue is being treated, and thusremoving the probe often causes repeat bleeding. Many such probes alsoproduce an undesirable buildup of eschar on or proximate the tip, whichdetrimentally affects the efficiency of the surgical instrument. Anothertype of instrument directs high frequency electric current through thetissue to stop bleeding. These instruments typically include at leastone electrode for contacting the tissue to be treated to establishelectrical communication with the tissue. Again, tissue adherence andeschar buildup may occur with these instruments.

Other instruments achieve coagulation by providing a gas to theatmosphere adjacent the targeted tissue. An ionizable gas, for exampleargon gas, may be directed toward the tissue past an electrode justprior to exiting a distal end of the instrument. An electrosurgicalcurrent may be conducted to the tissue through ionized conductivepathways in the gas without requiring direct contact between theelectrode and the tissue. Providing an atmosphere of ionized gas mayalso be beneficial, for example, since the gas displaces oxygen from thearea and reduces oxidative stress of the tissue.

The gas may be held in pressurized cylinders or tanks until a surgeon isready to begin treatment Relatively large cylinders may be fixed in onelocation or may be disposed on a movable cart in the operating room. Agas supply hose fluidly connects the remote cylinders to the instrument.Other configurations provide for a relatively small cylinder to behoused within a receptacle defined in a hand-held instrument. In eithercase, a seal in the cylinder may be ruptured to initiate the flow of thegas to the instrument. A substantial force, about 60 lbs in someinstances, may be required to rupture the cylinder seal. Providing sucha force may be difficult or distracting for a surgeon or supportclinician in an operating environment.

SUMMARY

The present disclosure describes a surgical instrument for providing agas to a surgical site. The instrument includes a receptacle forreceiving a cylinder of pressurized surgical gas, and a flame having aport near a distal end for emitting the surgical gas. An electrodedisposed adjacent the distal end of the flame is connected to a sourceof electrosurgical energy, and a passageway extends between thereceptacle and the port to deliver the surgical gas to the electrode. Apuncture assembly is provided for rupturing a seal defined by thecylinder to release the surgical gas into the passageway. The punctureassembly includes a spring movable between a first state for storingmechanical energy and a relaxed state, and an actuator operable to movethe spring to the relaxed state. A puncture pin is operatively coupledto the spring such that energy released by movement of the spring to therelaxed state is effective to move the puncture pin relative to thecylinder to rupture the seal.

The puncture pin may be operatively coupled to the spring with a gearrack and a pinion gear such that movement of the spring to the relaxedstate induces longitudinal motion in the gear rack, and longitudinalmotion in the gear rack induces rotational motion in the pinion gear.Also, the pinion gear may be operatively coupled to a cam shaft suchthat rotational motion in the cam shaft induces longitudinal motionbetween the puncture pin and the cylinder. The actuator may include aplunger configured to engage a slot in the cam shaft such thatdisengaging the plunger from the slot induces movement of the spring tothe relaxed state.

The receptacle may be configured to receive a plurality of cylinders andthe cam shaft may operatively engage a plurality of puncture pins suchthat each puncture pin is movable relative to a respective cylinder. Thepuncture pins may each move simultaneously with respect to one anotherrelative to the respective cylinder such that each of the cylinders ispunctured simultaneously. Alternatively, puncture pins may each movesequentially with respect to one another relative to a respectivecylinder such that each of the cylinders is punctured sequentially. Thecam shaft may include a radially offset cam surfaces such that each ofcam surfaces operatively engages a respective puncture pin to puncturethe cylinders sequentially.

The at least one spring may include a compression spring subject to acompressive force in the first state. Alternatively, the at least onespring may include an extension spring subject to a tensile force whenin the first state.

The surgical instrument may be configured such that the receptacle isdisposed within the frame. Alternatively, the receptacle may be disposedremotely with respect to the flame, and the passageway may include a gassupply hose fluidly connecting the receptacle with the frame.

The surgical instrument may be configured such that the source ofelectrosurgical energy is disposed within the frame. Alternatively, thesource of electrosurgical energy may be remotely coupled to the frame bya cable.

According to another aspect of the disclosure, a surgical instrument forproviding a surgical gas to a surgical site includes a receptacle forreceiving a cylinder of pressurized surgical gas and a frame defining aport near a distal end for emitting the surgical gas. A passagewayextending between the receptacle and the port defined in the frame. Apuncture assembly is provided for rupturing the cylinder to release thesurgical gas into the passageway. The puncture assembly includes a bankfor storing mechanical energy, an actuator responsive to an actuationforce to release the mechanical energy from the bank, and a puncture pinoperatively coupled to the bank such that the release of energy from thebank moves the puncture pin relative to the cylinder with a punctureforce greater than the actuation force. The bank may include at leastone spring movable between a compressed state for storing mechanicalenergy and a relaxed state.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate embodiments of the presentdisclosure and, together with the detailed description of theembodiments given below, serve to explain the principles of thedisclosure.

FIG. 1A is a schematic view of an electrosurgical coagulator accordingto the present disclosure depicting a gas cylinder and puncture assemblyincorporated into a hand-held applicator;

FIG. 1B is a schematic view of an alternate embodiment of the hand-heldapplicator of FIG. 1A including an electrosurgical generatorincorporated therein;

FIG. 2 is a schematic view of an alternate embodiment an electrosurgicalcoagulator in accordance with the present disclosure depicting the gascylinder and puncture assembly disposed remotely with respect to a handheld applicator;

FIG. 3 is an exploded, perspective view of the puncture assembly ofFIGS. 1 and 2;

FIG. 4 is a perspective view of the puncture assembly in an assembledconfiguration;

FIG. 5A is a schematic view of the gas cylinder and puncture assembly ina pre-set configuration wherein the gas cylinder is sealed;

FIG. 5B is an enlarged view of the area of detail identified in FIG. 5A;

FIG. 6A is a schematic view of the gas cylinder and puncture assembly inan actuated configuration wherein the gas cylinder is ruptured;

FIG. 6B is an enlarged view of the area of detail identified in FIG. 6A;

FIG. 7 is a schematic view of an alternate embodiment of a punctureassembly for sequentially rupturing a plurality of cylinders.

FIG. 8A is a schematic view of an alternate embodiment of a punctureassembly in a pre-set configuration wherein a hank of extension springsare in a first state for storing energy; and

FIG. 8B is a schematic view of the puncture assembly of FIG. 8A in anactuated configuration wherein the extension springs are in a relaxedstate.

DETAILED DESCRIPTION

Referring initially to FIG. 1A, an embodiment of an electrosurgicalinstrument is depicted generally as 10. The instrument 10 is dimensionedto resemble a pencil for hand-held or robotic manipulation for use inopen surgical procedures. However, it is envisioned that a similarinstrument may be configured, for example, with a pistol grip or otherhandle for use in laparoscopic or endoseopic surgical procedures.Further, although the basic operating features of instrument 10 aredescribed herein in connection to an open surgical procedure, the sameor similar operating features may be employed in connection with alaparoscopic or endoscopic procedure without departing from the scope ofthe present disclosure. The term “electrosurgical energy” herein refersto any type of electrical energy which may be utilized for medicalprocedures. The tern “proximal,” as is traditional, herein refers to theend of instrument 10 (or other element) which is closer to a user, whilethe term “distal” will refer to the end which is further from the user.

Instrument 10 includes an elongated housing 11 having a proximal end 12,a distal end 14 and an elongated cavity 15 extending therethrough. Thehousing 11 defines a receptacle 18 near the proximal end 12 forreceiving a gas container, canister, cartridge or cylinder 20. Cylinder20 contains a surgical gas, e.g., a noble or inert gas such as argon, ormixture of noble or inert gases. Cylinder 20 is relatively small,single-use and disposable. A rupture disk seal 22 at a forward end ofthe cylinder 20 exhibits a sufficient strength to maintain the requiredgas pressure in the cylinder 20. A gas pressure of about 3000 psi orless and a compressed gas volume of about 100 cubic centimeters or lesshave been found suitable for some coagulation procedures. To effectivelycontain the gas, rupture disk 22 may be constructed of a thin metalsheet such as stainless steel or beryllium copper.

The forward end of cylinder 20 is received by a puncture assembly 100.Puncture assembly 100 includes a threaded point 102 to positively engagethe forward end of cylinder 20. Alternatively, the use of spring clips,bayonet locks, friction fit or similar engagement arrangements are alsocontemplated. Puncture assembly 100 includes a release pin 104 extendingto an exterior of the housing 11 such that the release pin 104 isaccessible to a user during a coagulation procedure. Release pin 104 isoperable to selectively puncture rupture disk 22 and release the gasfrom cylinder 20 as described in greater detail below with reference toFIGS. 3 through 6. In other embodiments, the release pin 104 may beeliminated, and a plunger screw 176 may serve as a controlling featureto actuate a puncture assembly. Examples of such embodiments aredescribed below with reference to FIGS. 7 through 8B.

Adjacent puncture assembly 100 is a plenum 26, which receives thesurgical gas once rupture disk 22 is punctured. Plenum 26 communicateswith a regulator or valve 30 such that a flow rate of the surgical gasthrough the instrument 10 may be controlled. Regulator or valve 30includes an actuator 31 projecting outside the housing 11 to facilitateoperation by a user during a coagulation procedure. In fluidcommunication with the regulator or valve 30 is a gas supply tube 34,which extends generally longitudinally through housing 11 to the distalend 14. Gas supply tube 34 terminates proximally of a distal port 37defined at the distal end 14 of the housing 11. The distal port 37 isconfigured to emit, expel or disperse the surgical gas emanating fromthe gas supply tube 34 toward targeted tissue 40 at a surgical site.Distal port 37 may be configured to promote gas flow in a uniform andconsistent manner, or alternatively in a more turbulent manner.

The housing 11 supports an electrode 42 between the gas supply tube 34and the distal port 37. Surgical gas emanating from the gas supply tube34 is ionized by the electrode 42 before exiting the housing 11 throughthe distal port 37. The electrode 42 may alternatively be disposed onthe exterior of housing 11 near the distal port 37 such that surgicalgas emanating from the distal port 37 is ionized. The electrode 42 isconfigured as a substantially spherical member, but may alternatively beconfigured as a blade, needle or snare and may be suitable forfulguration, coagulation, cutting or sealing tissue.

A source of electrosurgical energy, generally designated “ESP,” supplieselectrode 42 with the electrosurgical energy to ionize the surgical gas.An electrosurgical generator 44 serves to produce the electrosurgicalenergy and also to control and monitor the delivery of theelectrosurgical energy. Various types of electrosurgical generators 44,such as those generators provided by Energy-based Devices, a globalbusiness unit, of Covidien, of Boulder, Colo., may be suitable for thispurpose. Electrosurgical generator 44 is electrically and mechanicallycoupled to the proximal end of housing 11 by a cable 48, whichelectrically communicates with a pair of leads 50, 52 on the interior ofthe housing 11. The two leads 50, 52 are coupled to an actuator such asbutton trigger 54. Trigger 54 is mounted on an accessible top side ofhousing 11, and is operable to selectively initiate and terminate thedelivery of electrossurgical energy from the electrosurgical generator44. Button trigger 54 may alternatively be configured as any other typeof known actuator, e.g., a rocker switch, dial, slide switch, etc. Whenthe trigger 54 is appropriately actuated, electrosurgical energy isdelivered to the electrode 42.

In an alternate embodiment depicted in FIG. 1B, an electrosurgicalgenerator 44B is adapted to be supported within the housing 11. Byproviding a source of electrosurgical energy within housing 11, thecable 48 (FIG. 1A) may be eliminated making the instrument lesscumbersome to operate in some instances.

As indicated above the surgical gas emanating from the distal port 37may be ionized by the electrode 42 when the electrode 42 isappropriately supplied with electrosurgical energy. The ionized gasforms plasma 56, which provides an electrical pathway between theelectrode 42 and the tissue 40 to be treated. Thus, electrosurgicalenergy may be conducted to the tissue 40 without physical contact withthe electrode 42 or housing 11.

As is common in monopolar electrosurgical systems, a return electrode orreturn pad 60 is positioned under the tissue 40 or generally under apatient. The return pad 60 is coupled to the electrosurgical generator44 by a cable 64. Cable 64 is, in turn, coupled to an appropriateelectrical potential provided by the generator 44 such that return pad60 provides an electrical return for the electrosurgical energy.

Referring now to FIG. 2, an alternate embodiment of an electrosurgicalinstrument is depicted generally as 70. Electrosurgical instrument 70includes a hand-held applicator 72 and a remote actuator assembly 76.The remote actuator assembly 76 includes one or more cylinders 20containing a surgical gas, and puncture assembly 100 for releasing thesurgical gas. Providing a remote actuator assembly 76 permits the use ofa larger gas supply than may conveniently be accommodated in thehand-held applicator, thus facilitating prolonged use of the instrument70. The remote actuator assembly 76 may include an actuator such as afoot switch, hand-held trigger, or other device that is operable toselectively initiate and terminate the delivery of electrosurgicalenergy from the electrosurgical generator 44.

The actuator assembly 76 is coupled to the electrosurgical generator 44by an electrical cable 78. The actuator assembly 76 may be positionednear the generator 44 such that actuator assembly 76 and the generator44 may be conveniently operated by a nurse or other support personnel.The actuator assembly 76 is coupled to the hand-held applicator 72 by agas supply hose 80 for the delivery of the surgical gas and anelectrical cable 82 for communicating electrosurgical energy,instructions and data.

The hand-held applicator 72 includes an elongated housing 84 and anelongated cavity 86 extending therethrough. Extending through thehousing 84 is a gas delivery tube 88 for transmitting the surgical gasbetween the gas supply hose 80 and the electrode 42. A distal point 37directs the surgical gas or plasma 56 toward the tissue 40 to be treatedas described above with reference to FIG. 1A. A return pad 60 and cable64 provide a return path to the generator 44 for electrosurgical energy.

The hand held applicator includes a single actuator 90, which isassociated with a valve or regulator to control the flow of surgicalgas. The actuator 90 extends to an accessible exterior of the housing 84to facilitate manipulation by a surgeon. It is also contemplated thatactuator assembly 90 may cooperate with one or more sensors 92, 94positioned near the distal poll 37 and within the supply tube 88respectively. Sensor 92 is configured to continually measure or monitora condition in the vicinity of the tissue 40 to be treated, e.g., theamount of tissue coagulation, and relay the information to generator 44through leads 96 and cables 82, 78. Generator 44 may include a controlsystem or safety circuit (not shown) in communication with the actuator90 such that the actuator 90 may be controlled by the generator 44 inresponse to a condition sensed by sensor 92. Similarly, sensor 94 may beemployed to measure a pressure or flow rate of surgical gas in thesupply tube 88, and relay the information to the generator 44.

Various additional and alternative aspects of the construction and useof a gas enhanced surgical instrument 10, 70 may be employed tofacilitate the treatment of tissue 40. Many of these aspects arediscussed in commonly-owned U.S. Provisional application Ser. No.12/240,252 bearing the publication No. 2009/0054893.

Referring now to FIGS. 3 and 4, puncture assembly 100 may be employed tobreach the rupture disk 22 (FIG. 1A) of a gas cylinder 20. The punctureassembly 100 includes a frame 110, which provides a mounting structurefor various other components of the puncture assembly 100. Generally,the frame 110 supports a cam shaft 112, a spring drive assembly 114 anda plunger assembly 116. The cam shaft 112 is mounted in a rotatablemanner about a first axis Al, and the spring drive assembly is mountedto support longitudinal motion about a second axis A2.

The cam shaft 112 includes three drum members 120. Each drum includes acircumferential cam surface 122 and a neutral surface 124. The camsurfaces 122 are sloped such that a radius of the respective drum member120 increases along the cam surface 122 while the neutral surfacesexhibit a constant radius. A longitudinal slot 126 extends along thedrum members 120 and separates the cam and neutral surfaces 122, 124.The drum members 120 also include a hexagonal drive bore 128 extendinglongitudinally therethrough. The drive bore of one of the drum membersis engaged by a head 130 of a hexagonal drive key 132 such that the drummember 120 rotates along with the drive key 132. Each of the drummembers 120 may be coupled to adjacent drum members 120 by a couplingmember (not shown) having a head similar to head 130 of drive key 132such that each of the drum members rotates together. Similarly, thedrive key 132 is engaged by a pinion gear 134 such that the drive key132 rotates with the pinion gear 134.

The frame 110 defines first and second bores 1110 a and 110 b forsupporting the cam shaft 112. A flanged bushing 136 is press fit intothe first bore 110 a and receives the drive key 132 such that the drivekey 132 is free to rotate therein. The drive key 132 is longitudinallysecured in the frame 110 with a washer 138 and screw 140 on one side ofthe bore 110 a and an E-ring on an opposite side of the bore 110 a. Thepinion gear 134 is secured to the drive key 132 between the bushing 136and the E-ring 142. A flanged bushing 146 is press fit into the secondbore 110 b. The bushing 146 receives a hexagonal cap 148 such that thehexagonal cap 148 is free to rotate therein. A screw 150 secures thehexagonal cap 148 to a drum member 120 via a coupling member (not shown)having a head that extends into an interior portion the hexagonal cap148.

This arrangement permits each drum member 120, the drive key 132, piniongear 134 and hexagonal cap 148 of the cam shaft 112 to rotate together.In other embodiments, a cam shaft (not shown) may be configured suchthat each drum member 120 rotates independently or in anotherarrangement to facilitate the puncture of multiple cylinders.

Rotation in the cam shaft 112 may be induced by operation of the springdrive assembly 114. The drive assembly 114 includes a bank of fourcompression springs 152, which, in combination, have the capacity tostore sufficient energy to permit the puncture assembly 100 to punctureat least one rupture disk seal 22 (FIG. 1A). In alternative embodiments,including the embodiment discussed below with reference to FIGS. 8A and8B, sufficient energy may also be stored by springs in an elongated ortensile state.

The drive assembly 114 includes an elongate support plate 154 fixedlymounted to the frame 110 by a coupling member 156 and screws 158. Thesprings 152 are supported on a first L-bracket 160 that is fixedlymounted to the elongate support plate 154 with screws 162. A secondL-bracket 164 opposes the first L-bracket 160 and engages the springs152 such that the second L-bracket 164 is longitudinally movable in thedirection of the second axis A2. The longitudinal position of the secondL-bracket 164 depends on the degree of compression in the springs 152. Agear rack 166 is fixedly coupled to the second L-bracket 164 such thatthe gear rack 166 moves longitudinally with the second L-bracket 164.The gear rack 166 moves longitudinally within a slot 168 defined in arack placement bracket 170. The rack placement bracket 170 is fixedlycoupled to the frame 110.

The gear rack 166 of the drive assembly 114 engages the pinion gear 134of the cam shaft 112 such that longitudinal motion in the drive assembly114 induces rotational motion in the cam shaft 112. Longitudinalmovement of the gear rack 166 in the direction of arrow L1 inducesrotational motion of the cam shaft 112 in the direction of R1.Similarly, movement of the gear rack 166 in the direction of arrow L2induces motion of the cam shaft in the direction of arrow R2.

The plunger assembly I 16 engages the cam shaft 112 as the cam shaft 112rotates. The plunger assembly 116 includes a knob support plate 172fixedly coupled to the frame 110 with screws 174. The knob support plate172 receives a spring-loaded plunger screw 176. The plunger screw 176 ispositioned such that a head 180 of the plunger screw 176 engages a drummember 120 along the cam surface 122 as the cam shaft 112 rotates freelyin the direction of arrow R1 or R2. As the plunger screw 176 encountersthe slot 126 of the drum member 120, however, the head 180 extends intothe slot 126 to prevent further rotational motion of the cam shaft 112.

Referring now to FIG. 5A, the puncture assembly 100 may be moved to apre-set configuration wherein the springs 152 are in a compressed stateand store energy. The gear rack 166 and second L-bracket 164 are movedin the direction of arrow L2 to a pre-set position. Release pin 104engages the second L-bracket 164 to prevent motion of the drive assembly114. The head 180 of the plunger screw 176 engages the cam surface 122of one of the drum members 120.

At least one cylinder 20 is screwed into the port 102 approximate thecam shaft 112. Multiple ports 182 may be provided to accommodateembodiments wherein multiple cylinders 20 are to be punctured. A plug182 may be provided to prevent gas leakage through any un-used port 102.A puncture pin 184 is disposed within the poll 102. As depicted in FIG.5B, the puncture pin 184 includes a sharpened tip portion 184 a and ahead portion 184 b extending out of the port 102. The sharpened tipportion 184 a is disposed toward the rupture disk seal 22 and forms aradial seal with an o-ring 186 or similar component. The o-ring 186inhibits leakage of any surgical gas released from cylinder 20 from apassageway 188 leading to plenum 26 (FIG. 1A) or gas supply hose 80(FIG. 2). The head portion 184 b of the puncture pin 184 engages the camsurface 122 of one of the drum members 120. The drum members 120 arepositioned such that the head portion 184 b engages the cam surface 122at a location where the radius of the drum member is at a minimum. Abiasing member (not shown) may be provided such that the head portion184 b maintains contact with the cylinder 120 as the cam shaft 112rotates.

Referring now to FIGS. 6A and 6B, the puncture assembly 100 may beactuated to puncture the rupture disk seal 22. The release pin 104 ismoved to an actuated position wherein the release pin 104 is disengagedfrom the second L-bracket 164. The energy stored in springs 152 isthereby released, driving the second L-bracket 164 and the gear rack 166in the direction of arrow L1. The motion of the gear rack 166 causes thepinion gear 134 (FIG. 3) and cam shaft 112 to rotate in the direction ofarrow R1 (FIG. 4). The cam surfaces 122 of the drum members 120 drivethe puncture pin 184 toward the cylinder 20. The springs 152 impart asufficient torque to the cam shaft 112 to drive the tip portion 184 athrough the rupture disk seal 22. Surgical gas is then released from thecylinder 20 into the passageway 188 leading toward the plenum 26 (FIG.1A) or gas supply hose 80 (FIG. 2). The head 180 of plunger screw 176engages the slot 126 in one of the drum members 120 to prevent anyover-travel of the cam shaft 112.

In this manner, an operator may puncture the cylinder 20 with arelatively small input force imparted to the release pin 104. The inputforce is sufficient to actuate the springs 152, but not necessarilysufficient alone to drive puncture pin 184 through the rupture disk seal22. This arrangement may facilitate operation of an electrosurgicalinstrument 10 (FIG. 1A) during a surgical procedure.

To reset the puncture assembly 100 once the release pin 104 is removed,the springs 152 may be compressed, and the release pin 104 may bereplaced at a convenient time prior to further surgical procedures. Insome embodiments, the user may have access to the mechanisms required toreset the puncture assembly 100. In other embodiments, the user may beeffectively locked out, thus requiring the instrument 10 to be rebuiltor refurbished by the manufacturer in order to reset the punctureassembly 100.

The number of springs 152 or the spring constant of the springs 152 maybe varied to configure the puncture assembly 100 to store a sufficientamount of energy to puncture a particular type of cylinder or cylinders20. Additionally, the pitch of the gear rack 166 and pinion gear 134 maybe varied to accommodate the various puncture forces that may berequired.

Referring now to FIG. 7, an alternate embodiment of a puncture assemblyis depicted generally as 200. Puncture assembly 200 is configured tosequentially puncture a series of cylinders 20. The cylinders 20 arescrewed into a frame 210 having ports 212 similar to ports 102 describedabove with reference to FIG. 5B. The ports 212 are in fluidcommunication with a passageway 220 leading toward the plenum 26 (FIG.1A) or gas supply hose 80 (FIG. 2), and puncture pins 184 are disposedwithin the ports 212. A bank of springs 152 is provided to store energyfor driving gear rack 166 in a longitudinal direction as described abovewith reference to FIG. 6. Longitudinal motion of the gear rack 166induces rotational motion of a cam shaft 222 by engaging a pinion gear(not shown) similarly configured and positioned as the pinion gear 134described above with reference to FIG. 4.

The cam shaft 222 includes three drum members 224A, 224B and 224C. Eachdrum member 224A, 224B and 224C includes a slot 226 defined therein, acam surface 228 and a neutral surface 230. The three drum members 224A,224B and 224C are configured to rotate together, but are oriented with aradial offset with respect to the neighboring drum members 224A, 224Band 224C. When the puncture assembly 200 is in a pre-set configuration,a first plunger screw 176 engages the slot 226 of drum member 224A, anda respective puncture pin 184 engages the cam surface 228 of the drummember 224A. The engagement of the first plunger screw 176 with the slot226 prevents rotation of the cam shaft 222 under the influence of theenergy stored in springs 152. Due to the radial offset of drum members224B and 224C, respective plunger screws 176 and puncture pins 184engage the neutral surfaces 230 of drum members 224B and 224C when thepuncture assembly 220 is in the preset configuration.

A first cylinder 20 may be punctured by disengaging the plunger screw176 from the slot 226 defined in drum member 224A. Disengagement of theplunger screw 176 permits rotation of the cam shaft 222 under theinfluence of the energy stored in springs 152. The cam surface 228 ofdrum member 224A drives the respective puncture pin 184 into thecorresponding cylinder 20 to release the surgical gas therefrom. Thedrum members 224B and 224C engage respective puncture pins 184 alongneutral surfaces 230 such that the respective puncture pins 184 do nottravel toward or puncture corresponding cylinders 20.

The cam shaft 222 continues to rotate until the slot 226 defined in drummember 224B encounters a respective plunger screw 176. The plunger screw176 then engages the slot 226 defined in drum member 224B and preventsfurther rotation of the cam shaft 222. The remaining energy stored insprings 152 is sufficient to puncture additional cylinders 20. As theplunger screw 176 is engaged with the slot 226 defined in drum member224B, the cam surface 228 of drum member 224B is positioned such thatfurther rotation of the cam shaft 222 drives the respective puncture pin184 toward the corresponding cylinder 20. Thus by sequentiallydisengaging the plunger screws 176 from the slots 226 defined in drummembers 224A, 224B and 224C, a plurality of cylinders 20 may besequentially ruptured.

Referring now to FIG. 8A, an alternate embodiment of a puncture assembly300 is depicted in a pre-set configuration. Puncture assembly 300includes a bank of extension springs 302 configured to store energy infirst tensile state. The springs 302 are provided in a stretchedconfiguration such that sufficient energy is stored in the springs 302to drive cam shaft 322 and puncture cylinder or cylinders 20.

In the pre-set configuration, springs 302 exert a force on the L-bracket164 in the direction of arrow L2. As in the embodiment described abovewith reference to FIG. 3, the L-bracket 164 is fixedly coupled to gearrack 166, and the gear rack 166 engages pinion gear 134 (FIG. 3) of camshaft 322. Thus, the force exerted by the springs 302 is transmitted tothe cam shaft 322. The cam shaft 322 is prevented from rotating underthe influence of this force by the head 180 of plunger screw 176extending into the longitudinal slot 126. An end opposite the head 180of the plunger screw 176 extends to an exterior of housing 11 such thatthe plunger screw 176 is accessible to a user during a coagulationprocedure. The user may manipulate the plunger screw 176 to draw thehead 180 from the slot 126 in the direction of arrow L3, and therebypermit the cam shaft 322 to rotate under the influence of the springs302. Thus, puncture assembly 300 is actuated by manipulating the plungerscrew 176.

Upon actuation of the puncture assembly 300, the puncture assembly 300moves from the pre-set configuration depicted in FIG. 8A to an actuatedconfiguration depicted in FIG. 8B. The springs 302 move to a relaxedstate drawing L-Bracket 164 and gear rack 166 in the direction of arrowL2. The longitudinal motion of the gear rack 166 induces rotationalmotion in the cam shaft 322 such that the orientation of the camsurfaces 122 and neutral surfaces 124 are reversed. The cam surfaces 124engage the puncture pins 184 as the cam shaft 322 rotates, and thepuncture pins 184 are driven toward the cylinders 20. Thus, thecylinders 20 are punctured when the user manipulates the plunger screw176. Puncture assembly 300 permits a user to puncture cylinders 20 byproviding only a force sufficient to remove the head 180 from the slot126. This arrangement may prove to be a viable alternative to directlypuncturing the cylinders 20.

Although the foregoing disclosure has been described in some detail byway of illustration and example, for purposes of clarity orunderstanding, it will be obvious that certain changes and modificationsmay be practiced within the scope of the appended claims.

What is claimed is:
 1. A surgical instrument for providing a gas to asurgical site, comprising: a receptacle for receiving a cylinder ofpressurized surgical gas; a frame having a proximal end and a distalend, the frame defining a port near the distal end for emitting thesurgical gas; an electrode disposed adjacent the distal end of theframe, the electrode adapted for connection to a source ofelectrosurgical energy; a passageway extending between the receptacleand the port defined in the frame, the passageway for delivering thesurgical gas to the electrode; and a puncture assembly for rupturing aseal defined by the cylinder to release the surgical gas into thepassageway, the puncture assembly comprising: at least one springmovable between a first state for storing mechanical energy and arelaxed state; an actuator operable to move the spring to the relaxedstate; and a puncture pin operatively coupled to the spring such thatenergy released by movement of the spring to the relaxed state iseffective to move the puncture pin relative to the cylinder to rupturethe seal.
 2. The surgical instrument according to claim 1, wherein thepuncture pin is operatively coupled to the spring via a gear rack andpinion gear such that movement of the spring to the relaxed stateinduces longitudinal motion in the gear rack, and longitudinal motion inthe gear rack induces rotational motion in the pinion gear.
 3. Thesurgical instrument according to claim 2, wherein the pinion gear isoperatively coupled to a cam shaft, and wherein rotational motion in thecam shaft induces longitudinal motion between the puncture pin and thecylinder.
 4. The surgical instrument according to claim 3, wherein theactuator includes a plunger configured to engage a slot in the cam shaftsuch that disengaging the plunger from the slot induces movement of thespring to the relaxed state.
 5. The surgical instrument according toclaim 3, wherein the receptacle is configured to receive a plurality ofcylinders, and wherein the cam shaft operatively engages a plurality ofpuncture pins such that each of the plurality of puncture pins ismovable relative to a respective cylinder.
 6. The surgical instrumentaccording to claim 1, wherein the receptacle is configured to receive aplurality of cylinders, and wherein the puncture assembly includes aplurality of puncture pins each movable simultaneously with respect toone another relative to a respective cylinder such that each of theplurality of cylinders may be punctured simultaneously.
 7. The surgicalinstrument according to claim 1, wherein the receptacle is configured toreceive a plurality of cylinders, and wherein the puncture assemblyincludes a plurality of puncture pins each movable sequentially withrespect to one another relative to a respective cylinder such that eachof the plurality of cylinders may be punctured sequentially.
 8. Thesurgical instrument according to claim according to claim 7, whereinmotion of the spring to the relaxed state induces rotational motion in acam shaft, the cam shaft including a plurality of cam surfaces radiallyoffset from one another, and wherein each of cam surfaces operativelyengages a respective puncture pin.
 9. The surgical instrument accordingto claim 1, wherein the at least one spring includes a compressionspring such that the compression spring is subject to a compressiveforce in the first state.
 10. The surgical instrument according to claim1, wherein the at least one spring includes an extension spring suchthat the extension spring is subject to a tensile force when in thefirst state.
 11. The surgical instrument according to claim 1, whereinthe receptacle is disposed within the frame.
 12. The surgical instrumentaccording to claim 1, wherein the receptacle is disposed remotely withrespect to the frame, and wherein the passageway includes a gas supplyhose.
 13. The surgical instrument according to claim 1, wherein thesource of electrosurgical energy is disposed within the frame.
 14. Thesurgical instrument according to claim 1, wherein the source ofelectrosurgical energy is disposed remotely with respect to the frameand coupled to the frame by a cable.
 15. A surgical instrument forproviding a surgical gas to a surgical site, comprising: a receptaclefor receiving a cylinder of pressurized surgical gas; a frame having aproximal end and a distal end, the frame defining a port near the distalend for emitting the surgical gas; a passageway extending between thereceptacle and the port defined in the frame; and a puncture assemblyfor rupturing a seal defined by the cylinder to release the surgical gasinto the passageway, the puncture assembly comprising: at least one bankfor storing mechanical energy; an actuator responsive to an actuationforce to release the mechanical energy from the bank; and a puncture pinoperatively coupled to the bank such that the release of energy from thebank moves the puncture pin relative to the cylinder with a punctureforce greater than the actuation force.
 16. The surgical instrumentaccording to claim 15, wherein the bank includes at least one springmovable between a compressed state for storing mechanical energy and arelaxed state.